The Uploader for Garmin, Version 4.2, supports direct upload to Endomondo. I've just published that version, so it may take a few hours before Google Play makes it available to you guys. An updated version of the tablet app (Sportablet) will follow.

Support for Endomondo is going to be in permanent beta. Endomondo does not officially support third party applications. Therefore, my code is tightly coupled to their current upload workflow. If they make relevant changes, integration may stop working until I go in, figure out what they changed and adapt my code. Just be aware of that and be kind if it happens :-), as the safe alternative would have been to say "no, you have to upload files manually".

I'm not a real Endomondo user myself, and so I'm not part of their community. I would appreciate if you could spread the news in forums, pages, etc.